Pttlverized-fuel-burning furnace



April 16, 1929. J BELL I I 1,708,929

PULVERIZED FUEL BURNING FURNACE Filed Nov. 11. 1920 I 4 Sheets-Sheet 2 MMEFS. INVETOR.

A TTORNEYS.

ATTORNEYS.

4 Sheets-Sheet l l INZENTOR.

J. E. BELL Filed Nov. 11, 1920 i PULVERI ZED FUEL BURNING FURNACE J. E. BELL April 16, 1929.

PULVERIZED FUEL BURNING FURNACE Filed Nov. '11.

1 4 Sheets-Shet 4 INVENTOR. 67M BY ATTORNEYS.

Patented Apr. 16, 1929.

UNITED STATES PATENT OFFICE.

JOHN E. BELL, F BROOKLYN, NEW YORK, ASSIGNOR TO COMBUSTION ENGIl lEEEING COMPANY, A CORPORATION OF NEW YORK.

PULVERIZED-FUEL-BURNIN G FURNACE.

Application filed November 11, 1920. Serial No. 423,235.

This invention relates to furnaces for burning pulverized. fuel, particularly such as are used in the generation of steam.

One of the primary objects of my invention resides in the provision of an improved arrangement of furnace by means of which it is not only possible to obviate the slagging difficulties which are ordinarily incident to the burning of pulverized fuel but .liciency.

One of the more specific objects of my in vention is to provide an improved form of water screen for pulverized fuel burning furnaces.

The foregoing, together with such other objects as may hereinafter appear, I ob tain by means of a construction, the pre ferred embodiments of which are illustrated in the accompanying drawings, wherein:

Fig. 1 is a longitudinal section through a portion of a furnace embodying my improvements, taken on the line 1 1. of Fig. 2; Fig. 2 is a front elevation of Fig. 1; Fig. 3 is a sectional. view corresponding to Fig. l but illustrating my invention with a modified form of boiler connection; Fig. at is a section on the line 4.& of Fig. 3; Fig. 5 is a fragmentary section illustrating still another modification of boiler connection; Fig. 6 is a section through a boiler illustrating another embodiment of the invention; and Fig. 7 is a section on the line 7--7 of Fig. 6.

Referring now to Figs. 1 and 2, the combustionichamber A of the steam generating furnace, indicated as a whole by the r\ .1- once letter B, is provided with an inlet burner G, preferably located in the top thereof, the number of said burners being varied as required. The burner (or burners) C is or are also located adjacent the front wall 1 of the combustion chamber so that the entering fuel or mixture of fuel and air will be subject to the radiant heat of such. wall. The combustion chamber is provided at the top with an outlet 2 for the hot gases and other products of combustion which are drawn off under the influence of the draft, and above such outlet I arrange anyrsuitable boiler setting such as the tubes 3 and headers 33. The mixture of fuel and air, or just the fuel itself, is admitted through pipe l and the flow thereof is aided, if desired, by means of a steam jet 5 or the like, in which connection I prefer that the also to greatly increase the evaporative efjet shall not be of high velocity. Supplemental air inlets 6 and 7 are provided for the burner and these, if desired, may be controlled by dampers 8.

Located in the wall 1 of the combustion chamber I provide a plurality of supplemental air inlets 9 for supplying such auxiliary air as may be necessary to complete combustion, such inlets being controlled by dampers 10 which, if desired, may be operated in unison, as by means of a chain 11.

The water screen for the combustion chamber composed of tubes 13 and tubes 13", such tubes being located some distance above the floor 12 of the combustion chamber. The tubes 15 slope slightly upwardly from the header 16 in the side wall 1st of the combustion chamber to the header 1? in the front wall 1, while the tubes 13" slope upwardly from the header 17 to the'header 16". Certain of the boiler tubes 3 broken out so that the pipes 18" and 15-) may be connected to'respective headers 16 and 16. In the constructimi. of Figs. 1 and 2, three of each of such pipes are provided, the outside pipes being connected to the corner boiler tubes which is advantageous in that such tubes are subjected to less temperature and therefore do not carry so much steam. Circulation takes place in the direction of the arrows, as will be readily understood.

The water screen has double function in that it prevents the products of combustion which may be deposited on the floor of the combustion chamber from turning into a solid mass of slag, ditlicult of removal, as will further appear, and it also increases the evaporative capacity of the furnace.

Since the surfaces of the tubes comprising the water screen are relatively cool as compared with the temperature of the furnace combustion chamber, the gravitating forming refuse as well as that which may be carried along with the flames in proximity to the tubes, will be subjected to the cooling action of the tubes and the deposit, which can be readily removed through the door 15, is largely in the form of small individual lumps or nodules of slag or slag-like matter, the temperature of which, as a result of the absorption of the radiant heat by the tubes, will be maintained below the tem perature at which the lumps will melt and run together, and thus fusing or coahescing of the deposit into a mass of liquid slag will permit the vto expand and pass more freely into the which solidifies into a cake on cooling is prevented. At the same time the chilling effect of the tubes on the flames themselves will have the efi'ect of arresting or partly arresting the flames.

The arrangement of screen is such as to greatly increase the number of tubes and it will be seen that such tubes are subject to the heat from the flames as well as the radiantheat from the floor so that an increase in evaporation is secured. .his end is further served by locating the pipes 19 within the chamberand adjacent the walllS.

Still greater elliciency is obtainedif the number of the pipes 19" be as illustrated in Figs. 3 and l, for such arrangement,- in ad dition to increasing the absorption areas, steam generated in the screen boiler. More rapid and adequate circulation through the screen is thus ensured and general efficiency enhance l. Instead of the form of connection shown in Figs. 1 and 2, headers 18 and 19 of 3 and lor the arrangement of Fig. 5, may be used.

1 prefer to form the side walls the furnace with the reentrant portions near the bottom so that the slag which forms on the walls thereabove will drip off and be subjected tot-he cooling action of the water screen.

in the modif'cation shown in Figs. (3 and 7, the headers 16 and 16 for the tubes 13 and 13 are located in the rear face of the Wall ll. and connections to the boiler are arranged as follows :A pair of headers 21 and 22 are anchored, approximately at the 'l'loorline, in the chamber B formed by the bridge walls is and 14" and the floor 14;. Pipes 18 preferably four in number bent in the shape indicated in Figs. 6 and 7, connect the headers 21 and 16*, substantially similar pipes 19 connecting headers and 16". Clover leaf headers 23 and 24.- are anchored to the bridge walls l-fl and 14; spectively, there preferably being four of such headers, in each group, pipes 18 connecting the headers 23 to header 21 and Di )es 19 connectin the headers 21 to header Tie shape of these pipes is shown. in. Fig. 7. Each oft-he clover leaf headers is connected with a plurality of the corner tubes of the boiler.

The advantages of this arrangement are that expansion is taken care of without un due expansion 111 any one direction and working on the ends of the tubes expanded in the clever leaf headers is prevented. As before noted the connections are made to the corner tubes which carry the least steam which frees the screen more freely of its steam and secures more uniform working of the tubes.

It will also be noted. that the tubes of the boiler are bailed at 25, 26 and 27 so as to cause the hot gases to flow through chamber B subjecting the pipes located therein to their heat.

No claim is made herein to the particular arrangement of the upright tubes which connect the ll-shaped screen into the circulaof the boiler as this is embraced in the subject matter claimed in my copending application, Serial No. 588,564, iiled Septemher 16th, 1922.

Iclaim:

1. in a furnace for burning pulverized fuel, the combination of a boiler, a combustion chamber, a transverse water screen for cooling falling refuse passing out of the flame in regular continuous ope alien to the place of deposit beyond said screen, said screen comprising two oppositely inclined sets of tubes extending through the combustion chamber with the tubes of one set st ggercd with respect to the tubes of the other set, a common header for one end. of said tubes, a. header for each set at the other end, and means for connecting each of said. last two headers into the circulation of the boiler.

2. ln a furnace for burning pulreriaed fuel, and the like, the combination of a boiler, a combustion chamber, a transverse water screen for cooling refuse particles precipitating out of the flame to the place .of deposit below said screen, said screen comprising two oppositely inclined rows of tubes connected in series, at one end, the tubes of each row being laterally spaced and the rows being vertically spacedpthe tubes one row being staggered with respect to the tubes of the other row and the spacing of the tubes being such that the refuse particlcs precipitating out of the flame pass freely thcrcbetween to the point of deposit, and means whereby a circulation of water takes place thru said screen.

signed my name.

JOHN E. BELL. 

